1. Field of the Invention
The invention relates to an improved mechanism for controlling a valve actuated by a camshaft and more specifically to a mechanism to vary the amount of opening and/or timing of cam actuated valves.
2. Description of the Prior Art
It is well known in the internal combustion engine art that a more flexible control of the engine valves will provide improved power and economy at virtually all engine speeds and loads. One method of providing more flexible valve control is taught in U.S. Pat. Nos. 2,934,052 and 3,277,874. Therein the camshafts are provided with high and low lift lobes for actuating each of the engine valves and means selectively operative to shift from valve actuation by one of the lobes to valve actuation by other of the lobes for varying the amount of valve opening and/or valve timing in accordance with engine operating conditions. It is also well known in the internal combustion engine art that improved operating economy may be obtained by disabling the valves of selected cylinders during certain engine operating conditions, for example, when the engine is lightly loaded. Prior U.S. Patent art is replete with patents teaching valve disablement.
The above mentioned patent application, like this application, discloses a valve control mechanism including a camshaft having a high lift lobe and two low lift lobes, a rigid link defining a rocker arm with two first cam followers which cooperate with the low lift lobe, a second cam follower pivotally connected to the link, a latch carried by the link, and a solenoid for controlling the latch. In the valve control mechanism of the mentioned patent application, the second cam follower is pivotally supported by the rocker arm adjacent to the lash adjuster end of the rocker arm, the latch is positioned about mid-way between the two ends of the rocker arm, and the solenoid is supported by the valve head structure. In the improved valve control mechanism of this application, the latch is positioned adjacent to the lash adjuster end of the rocker arm by pivotally supporting the second cam follower at the other end of the link or rocker arm and the solenoid is supported on the lash adjuster piston, which piston moves vertically up and down to control lash in the valve gear train. This arrangement of the latch and solenoid reduces inertia of the rocker arm, reduces the distance between the latch linkage and solenoid armature, and minimizes relative movement between the solenoid armature and the latch linkage.